Anthony Josef Norris, a muralist who runs an arts nonprofit for children, in front of a mural he created at Ida B. Wells High School in San Francisco in 2009. Norris has been charged with possession of child pornography.

(06-02) 17:19 PDT SAN FRANCISCO -- The head of a San Francisco nonprofit group that teaches art to children has been charged with possessing child pornography, authorities said Thursday.

FBI agents traced Anthony Josef Norris' log-on name of "Spanky" to his home computer and discovered 600 pornographic images of children, according to an arrest warrant affidavit filed in federal court in San Francisco.

Norris, 46, who lives in San Francisco, surrendered Thursday to FBI agents.

Norris founded the nonprofit group Kid Serve Youth Murals about 12 years ago and is its director. He said in a 2009 interview with The Chronicle that his goal was to help youths from preschool to high school develop their design talent and create mosaic murals.

His arrest came one month after agents searched his home and allegedly found the photos on his computer.

Norris admitted that he had been downloading such images for about a decade, according to the complaint filed against him.

He appeared in federal court Thursday and was released after posting $200,000 bond. If convicted, he could face up to 10 years in prison.